U.S. patent application number 17/081977 was filed with the patent office on 2021-05-27 for foldable display device.
The applicant listed for this patent is InnoLux Corporation. Invention is credited to Yu-Chia Huang, Kuan-Feng Lee, Yuan-Lin Wu.
Application Number | 20210157367 17/081977 |
Document ID | / |
Family ID | 1000005238910 |
Filed Date | 2021-05-27 |
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United States Patent
Application |
20210157367 |
Kind Code |
A1 |
Wu; Yuan-Lin ; et
al. |
May 27, 2021 |
FOLDABLE DISPLAY DEVICE
Abstract
A foldable display device is provided by the present disclosure.
The foldable display device includes a foldable display panel and a
foldable cover. The foldable cover is adhered to the foldable
display panel. The foldable cover includes an inner substrate, an
outer substrate and a first adhesive. The first adhesive is
disposed between the inner substrate and the outer substrate. A
thickness of the first adhesive is ranged from 1 micrometer to 40
micrometers, and a ratio of the sum of the thickness of the first
adhesive and a thickness of the inner substrate to a thickness of
the foldable cover is greater than or equal to 0.5 and less than 1.
In addition, the foldable display device further includes a second
adhesive disposed between the foldable display panel and the
foldable cover.
Inventors: |
Wu; Yuan-Lin; (Miao-Li
County, TW) ; Huang; Yu-Chia; (Miao-Li County,
TW) ; Lee; Kuan-Feng; (Miao-Li County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
InnoLux Corporation |
Miao-Li County |
|
TW |
|
|
Family ID: |
1000005238910 |
Appl. No.: |
17/081977 |
Filed: |
October 27, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 7/022 20190101;
B32B 2255/26 20130101; B32B 2457/20 20130101; B32B 27/308 20130101;
G06F 1/1652 20130101; H01L 51/0097 20130101; B32B 17/10
20130101 |
International
Class: |
G06F 1/16 20060101
G06F001/16; H01L 51/00 20060101 H01L051/00; B32B 27/30 20060101
B32B027/30; B32B 17/10 20060101 B32B017/10; B32B 7/022 20060101
B32B007/022 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2019 |
CN |
201911159194.9 |
Claims
1. A foldable display device, comprising: a foldable display panel;
and a foldable cover adhered to the foldable display panel, the
foldable cover comprising: an inner substrate; an outer substrate;
and a first adhesive disposed between the inner substrate and the
outer substrate, wherein the first adhesive has a thickness in a
range from 1 micrometer to 40 micrometers, and a ratio of the sum
of the thickness of the first adhesive and a thickness of the inner
substrate to a thickness of the foldable cover is greater than or
equal to 0.5 and less than 1.
2. The foldable display device of claim 1, wherein the thickness of
the inner substrate is greater than a thickness of the outer
substrate.
3. The foldable display device of claim 1, wherein a Young's
modulus of the outer substrate is greater than a Young's modulus of
the inner substrate.
4. The foldable display device of claim 1, wherein the inner
substrate comprises a polymeric material.
5. The foldable display device of claim 1, wherein the inner
substrate comprises polyimide and the outer substrate comprises
glass.
6. The foldable display device of claim 1, wherein a thickness of
the outer substrate is greater than the thickness of the first
adhesive.
7. The foldable display device of claim 6, wherein a ratio of the
thickness of the outer substrate to the thickness of the first
adhesive is greater than 2 and less than or equal to 60.
8. The foldable display device of claim 1, wherein the thickness of
the inner substrate is greater than the thickness of the first
adhesive.
9. The foldable display device of claim 8, wherein a ratio of the
thickness of the inner substrate to the thickness of the first
adhesive is greater than 1 and less than or equal to 100.
Description
BACKGROUND OF THE DISCLOSURE
1. Field of the Disclosure
[0001] The present disclosure relates to a display device, more
particularly to a foldable display device.
2. Description of the Prior Art
[0002] Foldable electronic device or deformable electronic device
has become one of the topics in the new generation of electronic
technology recently. Relatively, the demands of the foldable
display device that can be integrated into the electronic device
are increased accordingly, and the lifespan and/or the reliability
of the foldable display device are also an important issue.
Therefore, to achieve the desired product specifications such as
deformable effect, life span, and display effect of the foldable
display device through the design of the materials and/or the
structures is the direction of development in the related
field.
SUMMARY OF THE DISCLOSURE
[0003] One of the purposes of the present disclosure is to provide
a foldable display device, wherein the related characteristics of
the foldable display device may be improved through a foldable
cover.
[0004] A foldable display device is provided by an embodiment of
the present disclosure. The foldable display device includes a
foldable display panel and a foldable cover. The foldable cover may
be adhered to the foldable display panel. The foldable cover
includes an inner substrate, an outer substrate and a first
adhesive. The first adhesive is disposed between the inner
substrate and the outer substrate. A thickness of the first
adhesive is ranged from 1 micrometer to 40 micrometers, and a ratio
of the sum of the thickness of the first adhesive and a thickness
of the inner substrate to a thickness of the foldable cover is
greater than or equal to 0.5 and less than 1.
[0005] A foldable display device is provided by another embodiment
of the present disclosure. The foldable display device includes a
foldable display panel, a foldable cover and a second adhesive. The
foldable cover is disposed on the foldable display panel. The
foldable cover includes an inner substrate, an outer substrate and
a first adhesive. The first adhesive is disposed between the inner
substrate and the outer substrate. The second adhesive is disposed
between the foldable display panel and the foldable cover.
[0006] These and other objectives of the present disclosure will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the embodiment that
is illustrated in the various figures and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 schematically illustrates a top view of a display
device according to a first embodiment of the present
disclosure.
[0008] FIG. 2 schematically illustrates a partial cross-sectional
view of the display device in a non-folded state according to the
first embodiment of the present disclosure.
[0009] FIG. 3 schematically illustrates a partial cross-sectional
view of the display device in a folded state according to the first
embodiment of the present disclosure.
[0010] FIG. 4 schematically illustrates a partial cross-sectional
view of a display device according to a second embodiment of the
present disclosure.
[0011] FIG. 5 schematically illustrates a partial cross-sectional
view of a display device in a non-folded state according to a third
embodiment of the present disclosure.
[0012] FIG. 6 schematically illustrates a partial cross-sectional
view of a display device according to a fourth embodiment of the
present disclosure.
[0013] FIG. 7A schematically illustrates a cross-sectional view of
a cover structure in a display device according to an embodiment of
the present disclosure.
[0014] FIG. 7B schematically illustrates a cross-sectional view of
a cover structure in a display device according to an embodiment of
the present disclosure.
[0015] FIG. 7C schematically illustrates a cross-sectional view of
a cover structure in a display device according to an embodiment of
the present disclosure.
[0016] FIG. 7D schematically illustrates a cross-sectional view of
a cover structure in a display device according to an embodiment of
the present disclosure.
[0017] FIG. 8 schematically illustrates a partial cross-sectional
view of a display device according to a fifth embodiment of the
present disclosure.
[0018] FIG. 9 schematically illustrates a partial cross-sectional
view of a display device according to a sixth embodiment of the
present disclosure.
[0019] FIG. 10 schematically illustrates a partial cross-sectional
view of a display device according to a seventh embodiment of the
present disclosure.
DETAILED DESCRIPTION
[0020] Certain terms are used throughout the description and
following claims of the present disclosure to refer to particular
elements. As one skilled in the art will understand, the equipment
manufacturers may refer to an element by different names. The
present disclosure does not intend to distinguish between elements
that differ in name but not function. In the following description
and in the claims, the terms "include" and "comprise" are used in
an open-ended fashion, and thus should be interpreted to mean
"include, but not limited to . . . ".
[0021] It will be understood that when an element or layer is
referred to as being "disposed on" or "connected to" another
element or layer, it can be directly on or directly connected to
the other element or layer, or intervening elements or layers may
be presented. In contrast, when an element is referred to as being
"directly on" or "directly connected to" another element or layer,
there are no intervening elements or layers presented.
[0022] The ordinal numbers used in the specification and the claims
such as "first" and "second" are used to modify the element in the
claims, which does not mean or represent that the requested element
has any previous ordinal number, nor does it represent the order of
one of the requested element and another one of the requested
element or the order in the manufacturing method. The ordinal
numbers are used only to discriminate a requested element having a
certain name from another requested element with the same certain
name.
[0023] It should be understood that although different technical
features are respectively described in the embodiments listed in
the following contents, the technical features can be mixed in
different ways or recombined with each other without conflicting
with each other.
[0024] Referring to FIG. 1 to FIG. 3, FIG. 1 schematically
illustrates a top view of a display device 101 according to a first
embodiment of the present disclosure, FIG. 2 schematically
illustrates a partial cross-sectional view of the display device
101 in a non-folded state, and FIG. 3 schematically illustrates a
partial cross-sectional view of the display device 101 in a folded
state. It should be noted that the cross-sectional view of the
display device 101 shown in FIG. 2 may for example be drawn along a
line A-A' shown in FIG. 1, but not limited thereto. As shown in
FIG. 1 to FIG. 3, a display device 101 is provided by the present
embodiment, wherein the display device 101 may include a display
panel 10 and a cover structure 20. The display device (such as the
above-mentioned display device 101 and the display devices in other
embodiments) of the present disclosure may be regarded as a
foldable display device, the display panel 10 may be regarded as a
foldable display panel, and the cover structure 20 may be regarded
as a foldable cover, but not limited thereto. The cover structure
20 may be disposed on the display panel 10. In some embodiments,
the cover structure 20 may be adhered to the display panel 10, but
not limited thereto. The cover structure 20 may include an inner
substrate 22, an outer substrate 26 and a first adhesive 24 (such
like an adhesive layer). In the present embodiment, the inner side
may be regarded as a side relatively close to the center of the
entire display device, and the outer side may be regarded as a side
relatively far from the center of the entire display device, but
not limited thereto. The first adhesive 24 may be disposed between
the inner substrate 22 and the outer substrate 26. It is worth
noted that the direction X may be orthogonal to the direction Y to
form a virtual plane (not shown). In the condition that the display
device 101 is not folded, the virtual plane is parallel to the
surface of the display device 101, and the direction Z may be
regarded as the normal direction of the plane formed of the
direction X and the direction Y, but not limited thereto.
[0025] In some embodiments, the display device 101 may further
include a second adhesive 30 (such like an adhesive layer) disposed
between the display panel 10 and the cover structure 20, and the
second adhesive 30 may be configured to adhere the inner substrate
22 to the display panel 10, but not limited thereto. The display
device 101 includes a display region RG1 and a peripheral region
RG2. In the display region RG1, as shown in FIG. 1, the display
device 101 may further include the plurality of display elements
LE, which, for example, emits a display light to implement a
display function. In some embodiments, the peripheral region RG2 is
adjacent to the display region RG1, and the display region RG1 may
be the region of the dotted frame indicated by the arrow RG1 shown
in FIG. 1, however, the shape of the display region RG1 of the
present disclosure is not limited to the shape of the dotted frame,
and may include various kinds of shapes according to the demands of
the design. In some embodiments, the peripheral region RG2 may
surround the display region RG1, and the peripheral region RG2 may
be regarded as the portion outside the dotted frame of the
above-mentioned display region RG1. In some embodiments, the
projection area of the cover structure 20 in the direction Z may be
greater than the display region RG1 of the display panel 10 to
protect the display region. In other embodiments, the projection
area of the cover structure 20 may be located in the peripheral
region RG2, such that the cover structure 20 may be less likely to
protrude from the display panel 10 when the display device 101 is
being folded, but not limited thereto. In addition, the shape of
the display device 101 in the top view is not limited to what is
shown in FIG. 1, and may include other suitable shapes according to
the demands of the design such as triangle, prism, trapezoid,
wedge, other polygons or irregular shapes with curved edge, but not
limited thereto.
[0026] In some embodiments, the display device 101 may include at
least one foldable region RG3 extending along a direction (such as
the direction Y), and the display device 101 may include at least
two non-foldable regions RG4 located at two opposite sides of the
foldable region RG3, but not limited thereto. In some embodiments,
the display device 101 may include a plurality of foldable regions
RG3 according to the demands of the design, and the plurality of
non-foldable regions RG4 may be located between the foldable
regions RG3. In addition, the display device 101 may be folded,
curved, stretched, flexed and/or rolled along a folding axis FX.
The folding axis FX may be overlapped with the foldable region RG3
in the direction Z, and the folding axis FX may extend along the
direction parallel to the extending direction of the foldable
region RG3, but not limited thereto. In addition, the display
device 101 may be folded inward or outward according to the demands
of the design. For example, when the folding axis FX is located at
a side of the cover structure 20 far from the display panel 10 (for
example, located above the top surface S6 of the outer surface 26),
the display panel 101 may be folded inward along the folding axis
FX (as shown in FIG. 3). Relatively, the folding axis FX may also
be located at a side of the display panel 10 far from the cover
structure 20, such that the display device 101 may be folded
outward along the folding axis FX. In addition, the folding angle
of the display device 101 may be adjusted according to the demands
of the design. For example, in the non-foldable regions RG4, the
top surfaces S6 (such as the top surface S6-1 and the top surface
S6-2) of the outer substrate 26 at two opposite sides of the
folding axis FX may be parallel to each other (as shown in FIG. 3)
or an included angle may exist therebetween, and the bottom
surfaces S5 (such as the bottom surface S5-1 and the bottom surface
S5-2) of the outer substrate 26 at two opposite sides of the
folding axis FX may be parallel to each other (as shown in FIG. 3)
or an included angle may exist therebetween. In some embodiments,
the folded state of the display device 101 may be that at least one
of the layers of the display device 101 is folded such that the
different portions of the surface of the layer may substantially be
parallel to each other, for example, the top surface S4-1 and the
top surface S4-2 of the first adhesive 24 in the non-foldable
regions RG4 may be parallel to each other, as shown in FIG. 3. In
such situation, a virtual circle VC may be shown, and the virtual
circle VC may be tangent to the top surface S4-1 and the top
surface S4-2 (for example, the virtual circle VC may be tangent to
the top surface S4-1 and the top surface S4-2 through the point P1
and the point P2). A virtual line LL may pass through the points of
tangency (such as the point P1 and the point P2) and the center of
the virtual circle VC, and the radius of the virtual circle VC may
be regarded as the radius of curvature R (for example, half of the
distance between the point P1 and the point P2) of the first
adhesive 24, but not limited thereto. In the present embodiment,
the virtual line LL may be overlapped with the folding axis FX. It
is worth noted that the above-mentioned method (forming a virtual
circle which is tangent to the surface of a layer to obtain the
radius of curvature of the layer) may be applied to other layers
(such as the inner substrate 22) to obtain the radius of curvature
of the other layers in the cover structure 20.
[0027] In some embodiments, the display panel 10 may include a
self-emissive display panel, a non-self-emissive display panel or
other suitable types of the display panels. The above-mentioned
self-emissive display panel may include light emitting diodes
(LED), but not limited thereto. The light emitting diode may for
example include mini-LED, micro-LED, organic LED (OLED), quantum
dot LED (QD-LED) or the combinations of the above-mentioned LEDs.
The above-mentioned non-self-emissive display panel may include
liquid crystal display element, electrophoresis display element,
microelectromechanical systems (MEMS) display element, electronic
ink display element or the combinations of the above-mentioned
elements, but not limited thereto. In some embodiments, the display
panel 10 may provide display function at a side of the display
panel 10 facing the cover structure 20, but not limited thereto. In
some embodiments, the display panel 10 may also provide display
function at a side of the display panel 10 far from the cover
structure 20. In other words, the display panel 10 may be a
single-sided display panel, a double-sided display panel or a
transparent display panel, but not limited thereto.
[0028] In some embodiments, the outer substrate 26 of the cover
structure 20 may provide the required effects such as the optical
requirements (such as the optical performance), the touch of use
and/or the scratch resistance, the first adhesive 24 of the cover
structure 20 may provide stress balance and the adhesion between
the inner ring and the outer ring of the device when the device is
being folded, and the inner substrate 22 of the cover structure 20
may serve as a buffer layer to against external force, so as to
protect the display panel 10, but not limited thereto. In other
words, the related characteristics (such as the folding effect,
reliability and/or the life span of the product) of the foldable
display device may be improved by the cover structure 20 formed of
multiple layers of materials. In some embodiments, the Young's
modulus of the outer substrate 26 may be greater than the Young's
modulus of the inner substrate 22, but not limited thereto. For
example, the Young's modulus of glass and sapphire glass may be
greater than or equal to 71.7 GPa, and the Young's modulus of
polyimide (PI), polyethylene naphthalate (PEN) and polycarbonate
(PC) may be less than 10 GPa, but not limited thereto. 1 GPa is
equal to 10.sup.6 Pa, and 1 Pa is equal to 1 newton per square
meter (1 N/m.sup.2).
[0029] In some embodiments, the materials of the inner substrate 22
and the outer substrate 26 may respectively include glass, rubber,
polymer materials (such as polyimide, polyethylene naphthalate,
polycarbonate, polyurethane, polydimethylenesiloxane and/or
polyethylene terephthalate (PET)), at least one of the
above-mentioned materials, the combinations of the above-mentioned
materials or other suitable materials, and the material of the
inner substrate 22 may be the same as the material of the outer
substrate 26 or different from the material of the outer substrate
26. For example, the inner substrate 22 may include polyimide, and
the outer substrate 26 may include glass in some embodiments, but
not limited thereto. In some embodiments, the outer substrate 26
may include polymethylmetacrylate (PMMA). The outer substrate 26
may have anti-scratch and/or optical functions. The inner substrate
22 and the outer substrate 26 may be a single layer or a
multi-layer structure formed of the above-mentioned materials, such
as epoxy resin, acrylic resin (such as PMMA), benzocyclobutene
(BCB), polyimide, polyester, and polydimethylsiloxane (PDMS), but
the present embodiment is not limited thereto. When the inner
substrate 22 and/or the outer substrate 26 include multi-layer
structure, the layers may be formed by coating.
[0030] The first adhesive 24 may include optical clear adhesive
(OCA), pressure sensitive adhesive (PSA) or other adhesive
materials having suitable characteristics. In addition, the first
adhesive 24 may be a transparent adhesive layer, and the material
of the first adhesive 24 may include acrylate, urethane-based
composition, acrylic-based composition, silicon-based composition
or may be formed of other suitable adhesive materials. The first
adhesive 24 may be a polymeric adhesive layer. In addition, the
material of the second adhesive 30 may be similar to the material
of the first adhesive 24, and the thickness and adhesive force of
the second adhesive 30 may be adjusted to be the same as or
different from the thickness and/or the adhesive force of the first
adhesive 24 according to the demands of the design.
[0031] As shown in FIG. 2, in some embodiments, the first adhesive
24 may be configured to adhere the inner substrate 22 to the outer
substrate 26, so the top surface S2 of the inner substrate 22 may
directly be in contact with the bottom surface S3 of the first
adhesive 24, and the bottom surface S5 of the outer substrate 26
may be directly in contact with the top surface S4 of the first
adhesive 24. The inner substrate 22, the first adhesive 24 and the
outer substrate 26 may respectively include a thickness T1, a
thickness T2 and a thickness T3 in the direction Z. In some
embodiments, the thickness T1 may be the distance from the bottom
surface S1 of the inner substrate 22 to the top surface S2 of the
inner substrate 22 in the direction Z under the condition that the
display device 101 is not folded, the thickness T2 may be the
distance from the bottom surface S3 of the first adhesive 24 to the
top surface S4 of the first adhesive 24 in the direction Z under
the condition that the display device 101 is not folded, and the
thickness T3 may be the distance from the bottom surface S5 of the
outer substrate 26 to the top surface S6 of the outer substrate 26
in the direction Z under the condition that the display device 101
is not folded. The position for measuring the thickness may be
located in the non-foldable region RG4 and/or the region of the
non-foldable region RG4 corresponding to the display region, and
the measurement may be performed by measuring the value of a single
point or obtaining the average of the values measured in multiple
points, but not limited thereto.
[0032] In some embodiments, the related characteristics (such as
folding effect, reliability and/or life span of the product) of the
display device 101 may be improved by controlling the thickness
conditions of the inner substrate 22, the first adhesive 24 and the
outer substrate 26 respectively, but not limited thereto.
[0033] In some embodiments, the thickness T1 of the inner substrate
22 may be greater than the thickness T3 of the outer substrate 26.
In some embodiments, the thickness T3 of the outer substrate 26 may
be greater than the thickness T2 of the first adhesive 24, and a
ratio (T3/T2) of the thickness T3 of the outer substrate 26 to the
thickness T2 of the first adhesive 24 may be greater than 2 and
less than or equal to 60, but not limited thereto. In some
embodiments, the thickness T1 of the inner substrate 22 may be
greater than the thickness T2 of the first adhesive 24, and a ratio
(T1/T2) of the thickness T1 of the inner substrate 22 to the
thickness T2 of the first adhesive 24 may be greater than 1 and
less than or equal to 100, but not limited thereto. A ratio of the
sum of the thickness T2 of the first adhesive 24 and the thickness
T1 of the inner substrate 22 to the thickness of the cover
structure 20 (such as the sum of the thickness T1, the thickness T2
and the thickness T3 mentioned above) may be greater than or equal
to 0.5 and less than 1, but not limited thereto. In other words, in
some embodiments, the thickness T1 of the inner substrate 22, the
thickness T2 of the first adhesive 24 and the thickness T3 of the
outer substrate 26 may meet the following equation (I), but not
limited thereto.
0.5.ltoreq.(T1+T2)/(T1+T2+T3)<1 (I)
[0034] The following table 1 shows the result of the ball drop test
of the inner substrate 22, the first adhesive 24 and the outer
substrate 26 under different thickness combinations and under the
condition that the inner substrate 22, the first adhesive 24 and
the outer substrate 26 are not folded. The ball drop rest may be
performed by using an object with a weight of about 8.5 grams to be
dropped from 10 centimeters or higher from the top surface S6 of
the outer substrate 26, thereby testing the ability of the cover
structure 20 to withstand external stress (for example, to test
whether the cover structure 20 may protect the display panel 10,
such that the display panel 10 may not be broken by the external
stress). In addition, in the ball drop test shown in table 1, the
material of the outer substrate 26 may be glass, the material of
the inner substrate 22 may be PET, and the adhesive force of the
first adhesive 24 may be about 10 gf/in, but not limited thereto.
As shown in FIG. 2 and table 1, the ratio of the sum of the
thickness T2 of the first adhesive 24 and the thickness T1 of the
inner substrate 22 to the thickness of the cover structure 20 (such
as the sum of the thickness T1, the thickness T2 and the thickness
T3 mentioned above) should be greater than or equal to 0.5 to pass
the ball drop test. It is worth noted that the thickness and/or the
adhesive force of the second adhesive 30 would not affect the
result of the ball drop test mentioned above in some embodiments,
so the adjustment of the thickness and/or the adhesive force of the
second adhesive 30 according to other demands of the design is not
considered. In other words, the effect of the thickness and/or the
adhesive force of the second adhesive 30 may be neglected, and the
main influencing factors may be the thickness T1 of the inner
substrate 22, the thickness T2 of the first adhesive 24, the
thickness T3 of the outer substrate 26 and the ratio relationship
thereof.
TABLE-US-00001 TABLE 1 combination 1 2 3 4 5 6 7 8 T3 (micrometer)
40 40 40 40 40 40 40 40 T2 (micrometer) 0.1 1 5 5 15 15 10 40 T1
(micrometer) 10 10 10 20 25 50 60 60 (T1 + T2)/(T1 + T2 + T3) 0.20
0.22 0.27 0.38 0.50 0.62 0.64 0.71 result Fail Fail Fail Fail
Passed Passed Passed Passed
[0035] The following table 2 shows the result of the ball drop test
under the condition that the thicknesses of the inner substrate 22,
the first adhesive 24 and the outer substrate 26 are fixed, and the
material of the inner substrate 22 is varied, wherein the Young's
modulus of the glass and the sapphire (Al.sub.2O.sub.3) glass used
may be greater than or equal to 71.7 GPa, and the Young's modulus
of the PI, PET and PC used may be less than 10 GPa, but not limited
thereto. As shown in FIG. 2 and table 2, the Young's modulus of the
inner substrate 22 should be less than 10 GPa to pass the ball drop
test, and the Young's modulus of the outer substrate 26 may be
greater than the Young's modulus of the inner substrate 22.
TABLE-US-00002 TABLE 2 combination 9 10 11 12 13 outer substrate
glass glass glass glass glass (40 micrometers) first adhesive
materials with materials with materials with materials with
materials with (10 micrometers) adhesive force adhesive force
adhesive force adhesive force adhesive force of 10 gf/in of 10
gf/in of 10 gf/in of 10 gf/in of 10 gf/in inner substrate glass
sapphire polyimide polyethylene polycarbonate (25 micrometers)
glass (PI) terephthalate (PC) (PET) result Fail Fail passed passed
passed
[0036] Besides, it is worth noted that the thickness of the first
adhesive 24 may be changed to provide stress balance when the
display device 101 is being folded, so the thickness T4 of the
first adhesive 24 in the foldable region RG3 may be less than the
thickness T2 of the first adhesive 24 in the non-foldable region
RG4, but not limited thereto. In some embodiments, the measuring
method of the thickness T4 mentioned above may include measuring
the thickness of the first adhesive 24 in the foldable region RG3
under the folded state (the folded state may for example be that at
least one of the layers of the display device 101 is folded such
that the different portions of the surface of the layer may
substantially be parallel to each other, for example, the top
surface S4-1 and the top surface S4-2 of the first adhesive 24 in
the non-foldable regions RG4 may be parallel to each other, as
shown in FIG. 3), and the measurement of the thickness may be
performed by measuring the value of a single point or obtaining the
average of the values measured in multiple points, but not limited
thereto.
[0037] The following table 3 shows the result of a folding test
under the condition that the thicknesses of the inner substrate 22
and the outer substrate 26 are fixed, and the thickness of the
first adhesive 24 is varied. The folding test may be performed by
folding the display device 101 to the most extreme state under the
condition that the radius of curvature R is about 1 millimeter
(mm), and the folding action is repeated about 100000 times,
thereby testing the reliability and life span of the cover
structure 20. In addition, in the folding test shown in table 3,
the material of the outer substrate 26 may be glass, the material
of the inner substrate 22 may be PET, and the adhesive force of the
first adhesive 24 may be about 10 gf/in, but not limited thereto.
As shown in FIG. 2, FIG. 3 and table 3, when the thickness T2 of
the first adhesive 24 is too thin (for example, the thickness T2 is
less than 1 micrometer), the thickness T4 of the first adhesive 24
in the foldable region RG3 may easily be insufficient during
folding, such that the friction between the outer substrate 26 and
the inner substrates 22 may be occurred, which leads to cracking of
the outer substrate 26 and the inner substrates 22. When the first
adhesive 24 is too thick (for example, the thickness T2 is greater
than 20 micrometers), the relative misalignment between the outer
substrate 26 and the inner substrate 22 may be too large to pass
the test. Therefore, the thickness T2 of the first adhesive 24
should be greater than or equal to 1 micrometer and less than or
equal to 40 micrometers to pass the folding test. It is worth noted
that the thickness and/or the adhesive force of the second adhesive
30 does not affect the result of the folding test mentioned above
in some embodiments, so the adjustment of the thickness and/or the
adhesive force of the second adhesive 30 according to other demands
of the design is not considered. In other words, the effect of the
thickness and/or the adhesive force of the second adhesive 30 may
be neglected, and the main influencing factors may be the thickness
T1 of the inner substrate 22, the thickness T2 of the first
adhesive 24, the thickness T3 of the outer substrate 26 and the
ratio relationship thereof.
TABLE-US-00003 TABLE 3 combination 14 15 16 17 18 19 20 21 T3
(micrometer) 40 40 40 40 40 40 40 40 T2 (micrometer) 0.1 0.5 0.8 1
5 10 40 50 T1 (micrometer) 40 40 40 40 40 40 40 40 result Fail Fail
Fail passed passed passed passed Fail
[0038] In some embodiments, the thickness T1 of the inner substrate
22 may range from 0.2 micrometer to 150 micrometers, the thickness
T2 of the first adhesive 24 may range from 0.1 micrometer to 40
micrometers, and the thickness T3 of the outer substrate 26 may
range from 20 micrometers to 100 micrometers, but not limited
thereto. It should be noted that "the thickness T1 of the inner
substrate 22 ranges from 0.2 micrometer to 150 micrometers"
mentioned above represents that the thickness T1 is greater than or
equal to 0.2 micrometer and less than or equal to 150 micrometers,
and all of the terms "range from" in the present specification can
be interpreted in the same way. In some embodiments, the thickness
T1 of the inner substrate 22 may range from 20 micrometers to 100
micrometers, the thickness T2 of the first adhesive 24 may range
from 1 micrometer to 40 micrometers, and the thickness T3 of the
outer substrate 26 may range from 40 micrometers to 60 micrometers,
but not limited thereto. In some embodiments, the thickness T1 of
the inner substrate 22 may range from 30% to 55% of the thickness
T5 of the cover structure 20 (for example,
30%.ltoreq.T1/T5.ltoreq.55%), the thickness T2 of the first
adhesive 24 may range from 1.6% to 35% of the thickness T5 of the
cover structure 20 (for example, 1.6%.ltoreq.T2/T5.ltoreq.35%), and
the thickness T3 of the outer substrate 26 may range from 20% to
50% of the thickness T5 of the cover structure 20 (for example,
20%.ltoreq.T3/T5.ltoreq.50%), but not limited thereto. It is worth
noted that the ranges of the thickness T1, the thickness T2 and the
thickness T3 mentioned above may be applied to the inner substrate
22, the first adhesive 24 and the outer substrate 26 in the
non-foldable region RG4 and/or the inner substrate 22, the first
adhesive 24 and the outer substrate 26 in the foldable region
RG3.
[0039] In addition, the adhesive force (AS) of the first adhesive
24 may range from 10 gram force per inch (gf/in) to 60 gf/in (for
example, 10 gf/in.ltoreq.AS.ltoreq.60 gf/in). In some embodiments,
the optical refractive indexes (for example, N=1.5) of the inner
substrate 22, the first adhesive 24 and the outer substrate 26 may
be similar to each other (for example, the refractive indexes are
within a range.+-.0.3, but not limited thereto), thereby reducing
the negative effects (such as the scattering of light) of the cover
structure 20 on the display, but not limited thereto.
[0040] As shown in FIG. 2, in some embodiments, the display device
101 may selectively include a release layer 32 disposed between the
second adhesive 30 and the inner substrate 22, and in order to
simplify the figure, the release layer 32 of the display device 101
in the folded state shown in FIG. 3 is omitted. In some
embodiments, the release layer 32 may directly be in contact with
the bottom surface S1 of the inner substrate 22, the release layer
32 may include hydrogen (for example, it may be a
hydrogen-containing amorphous silicon layer or other
hydrogen-containing material layer), and a laser annealing process
may be used to cause a hydrogen explosion at the interface between
the release layer 32 and the inner substrate 22, such that the
cover structure 20 may be detached from the display panel 10,
thereby reaching the effect of replacing the cover structure 20.
Through the replacing method, the risk of damage due to tearing of
the cover structure 20 by stress may be reduced. The laser
annealing process mentioned above may be performed at a side above
the display device 101, or may be performed at a side below the
display device 101. In addition, a laser process may be selectively
performed on local positions of the display device 101 to reduce
the adverse effects on the electrical elements in the display panel
10, but not limited thereto.
[0041] It is worth noted that each of the features of the display
device of the present disclosure may be applied to other kinds of
electronic devices such as smart window, antenna, touch device, and
etc. For example, the display layer of the display device may be
replaced with a working medium layer, and the working medium layer
may for example include liquid crystal of the liquid crystal
antenna, liquid crystal of the liquid crystal window or other
working mediums with specific functions.
[0042] Different embodiments of the present disclosure will be
described in the following, and in order to simplify the
description, the differences between each of the embodiments will
be described in detail, and the repeated features will not be
redundantly described. In addition, the label of the same elements
in each of the embodiments of the present disclosure would be the
same in order to facilitate the comparison between each of the
embodiments. The features in each of the embodiments may be mixed
or combined without departing from the spirit of the present
disclosure or conflicting with each other.
[0043] Referring to FIG. 4, FIG. 4 schematically illustrates a
partial cross-sectional view of a display device 102 according to a
second embodiment of the present disclosure. As shown in FIG. 4, in
some embodiments, the display panel 10 may include a display layer
12 and a flexible substrate 15, and the display layer 12 may be
disposed between the flexible substrate 15 and the cover structure
20. The display layer 12 may include self-emissive display element,
non-self-emissive display element or other suitable types of the
display structures. The above-mentioned self-emissive display
element may include light emitting diode, but not limited thereto.
The light emitting diode may for example include mini light
emitting diode, micro light emitting diode, organic light emitting
diode, quantum dot light emitting diode or the combinations of the
above-mentioned LEDs, but not limited thereto. The above-mentioned
non-self-emissive display element may include liquid crystal
display element, electrophoresis display element,
microelectromechanical systems display element, electronic ink
display element or the combinations of the above-mentioned
elements, but not limited thereto.
[0044] The cover structure 20 and the flexible substrate 15 may
respectively include a thickness T5 and a thickness T6 in the
direction Z. In some embodiments, the thickness T5 may be equal to
the sum of the thickness T1, the thickness T2 and the thickness T3
mentioned above, but not limited thereto. In some embodiments, the
thickness T6 may be the distance from the bottom surface S7 of the
flexible substrate 15 to the top surface S8 of the flexible
substrate 15 in the direction Z under the condition that the
display device 102 is not folded, and the measuring method of the
thickness T6 may be similar to the measuring method of the
thickness T1, the thickness T2 and the thickness T3 mentioned
above, which will not be redundantly described here. In addition,
the display device 102 may include a center line CL bended
according to the folding condition, and the stress on the layers at
two sides of the center line CL may be greater. In some
embodiments, a ratio of the thickness T5 of the cover structure 20
to the thickness T6 of the flexible substrate 15 (T5/T6) may be
greater than or equal to 0.8 and less than or equal to 1.2, such
that the center line CL of the display device 102 may be located at
the display layer 12, thereby reducing the possibility of damage of
the display layer 12 caused by the stress when the display device
102 is being folded, but not limited thereto. In some embodiments,
the center line CL may be regarded as the center line of the
thickness of the entire display device 102 in the direction Z, but
not limited thereto. In some embodiments, the center line CL may be
a neutral plane of the display device 102, and may be regarded as
the position where the compressive stress and the tensile stress
are balanced, but not limited thereto.
[0045] In some embodiments, the flexible substrate 15 may include
single layer material structure or multi-layers material structure.
For example, the flexible substrate 15 may include a first
substrate 14, a third adhesive 16 (such like an adhesive layer) and
a second substrate 18, the third adhesive 16 may be disposed
between the first substrate 14 and the second substrate 18, and the
first substrate 14 may be disposed between the third adhesive 16
and the display layer 12. Therefore, the bottom surface S7 of the
flexible substrate 15 may be the bottom surface of the second
substrate 18, and the top surface S8 of the flexible substrate 15
may be the top surface of the first substrate 14, but not limited
thereto. The materials of the first substrate 14 and the second
substrate 18 may respectively include glass, rubber, polymeric
materials such as PI, PEN, PC, polyurethane, polydimethylsiloxane
and/or PET, at least one of the above-mentioned materials, the
mixture of the above-mentioned materials or other suitable
materials, and the material of the first substrate 14 and the
material of the second substrate 18 may be the same or different.
The material of the third adhesive 16 may be similar to the
material of the first adhesive 24 mentioned above, but not limited
thereto. When the display panel 10 is a single-sided display panel,
the third adhesive 16 may include opaque adhesive materials. When
the display panel 10 is a double-sided display panel or a
transparent display panel, the third adhesive 16 may include
transparent adhesive materials, but not limited thereto.
[0046] Referring to FIG. 5, FIG. 5 schematically illustrates a
partial cross-sectional view of a display device 103 in a
non-folded state according to a third embodiment of the present
disclosure. In some embodiments, the cover structure 20 may include
at least one first recess (such as the recess RC1 in the inner
substrate 22 and/or the recess RC2 in the outer substrate 26)
corresponding to the folding axis FX. That is, the recess RC1
and/or the recess RC2 may be overlapped with the folding axis in
the direction Z. For example, the inner substrate 22 may include a
recess RC1 corresponding to the folding axis FX, and the outer
substrate 26 may include a recess RC2 corresponding to the folding
axis FX, but not limited thereto. In some embodiments, only the
recess RC1 is disposed in the inner substrate 22 or only the recess
RC2 is disposed in the outer substrate 26 according to the demands
of the design. The recess RC1 of the inner substrate 22 is the
recess of the top surface S2 toward a direction approaching the
display panel 10, and the recess RC2 of the outer substrate 26 is
the recess of the bottom surface S5 toward a direction away from
the display panel 10, so a portion of the first adhesive 24 may be
disposed in the recess RC1 of the inner substrate 22 or in the
recess RC2 of the outer substrate 26, but not limited thereto. In
some embodiments, the thickness H1 of the recess RC1 and/or the
thickness H2 of the recess RC2 may be less than 100 micrometers,
for example, the thickness H1 may range from 50 micrometers to 80
micrometers, and the thickness T1 of the inner substrate 22 and/or
the thickness T3 of the outer substrate 26 may range from 300
micrometers to 2000 micrometers, but not limited thereto. It is
worth noted that the measuring method of the thickness of the
above-mentioned recesses may include measuring the distance from
the bottom surface of the recess to the corresponding surface, but
not limited thereto. For example, the thickness H1 of the recess
RC1 may be the distance from the bottom surface of the recess RC1
to the bottom surface S1 of the inner substrate 22, and the
thickness H2 of the recess RC2 may be the distance from the bottom
surface of the recess RC2 to the top surface S6 of the outer
substrate 26, but not limited thereto. In addition, a ratio of the
thickness H1 of the recess RC1 to the thickness T1 of the inner
substrate 22 (such as H1/T1) may be greater than or equal to 0.02
and less than or equal to 0.2, and a ratio of the thickness H2 of
the recess RC2 to the thickness T3 of the outer substrate 26
(H2/T3) may be greater than or equal to 0.02 and less than or equal
to 0.2, but not limited thereto. It is worth noted that the range
of the thickness T1 and the range of the thickness T3 mentioned
above may be applied to the inner substrate 22 and the outer
substrate 26 located in the non-foldable region RG4 in the present
embodiment.
[0047] In addition, the first adhesive 24 may include a radius of
curvature R under a folding condition, and the width W1 of the
recess RC1 may meet the following equation (II), but not limited
thereto.
0.8.pi.R.ltoreq.W1.ltoreq.1.5.pi.R (II)
[0048] In addition, in some embodiments, the flexible substrate 15
may include a second recess (such as the recess RC3) corresponding
to the folding axis FX of the cover structure 20, the recess RC3
may be the recess of the bottom surface (such as the bottom surface
S7 of the second substrate 18) of the flexible substrate 15 toward
a direction approaching the cover structure 20, but not limited
thereto.
[0049] A ratio of the width (such as the width W1 of the recess RC1
and/or the width W2 of the recess RC2) of the recesses mentioned
above to the width W3 of the recess RC3 (such as W1/W3 and/or
W2/W3) may be greater than or equal to 0.7 and less than or equal
to 1.3, but not limited thereto. In some embodiments, the width W1,
the width W2 and/or the width W3 mentioned above may be less than
the width W4 of the foldable region RG3 in the direction X under
the condition that the foldable region RG3 is not folded (as shown
in FIG. 5), but not limited thereto. In some embodiments, the width
W1, the width W2 and/or the width W3 may be greater than or equal
to the width of the foldable region RG3 in the direction X under
the condition that the foldable region RG3 is not folded according
to the demands of the design. It is worth noted that the measuring
method of the width of the recesses mentioned above may include
measuring the width of the recess from a starting point where the
slope of the surface of the recess start changing (compared with
the slope of a flat surface), but not limited thereto.
[0050] In some embodiments, the junction of the recess RC1 and the
flat region of the inner substrate 22 may include arc-shaped edge
CE, thereby reducing the possibility of damage caused by the
friction between the inner substrate 22 and the outer substrate 26
when a folding is performed because the shape of the junction
mentioned above is too sharp. In other embodiments, the junction of
the recess RC2 and the flat region of the outer substrate 26 and/or
the junction of the recess RC3 and the flat region of the flexible
substrate 15 may also include arc-shaped edge, but not limited
thereto. In addition, the recess RC1, the recess RC2 and/or the
recess RC3 mentioned above may be overlapped with the folding axis
FX in the direction Z, but not limited thereto. In some
embodiments, the recess RC1, the recess RC2 and the recess RC3 may
respectively extend along the direction Y (drawn in FIG. 1), and
the recess RC1, the recess RC2 and the recess RC3 may respectively
include linear patterns, folded patterns, block patterns or other
suitable shapes. Through disposing the recess RC1, the recess RC2
and the recess RC3 and controlling the thickness and/or the width,
the foldable property of the display device 103 may be improved
without affecting the protecting effect of the non-foldable region
RG4.
[0051] In some embodiments, the display device 103 may selectively
include a functional layer 40 disposed on the flexible substrate
15, and the functional layer 40 may include single layer structure
or multi-layers structure to provide specific functions, but not
limited thereto. For example, the functional layer 40 may include
touch sensing layer, polarizer, retardation layer (such as an
optical retardation layer, wherein the optical retardation layer
may include .lamda./2 retardation layer and/or .lamda./4
retardation layer), anti-reflection layer and/or other functional
layers providing other functions. In some embodiments, the
functional layer 40 may be disposed between the cover structure 20
and the foldable display panel 10. In some embodiments, the
functional layer 40 may be disposed between the second adhesive 30
and the foldable display panel 10. In some embodiments, the
functional layer 40 may be included in the cover structure 20 or
may be regarded as at least a portion of any one of the substrate
of the cover structure 20, but not limited thereto. In the present
disclosure, the relative position of the functional layer 40 in the
display device and/or the relative position of each of the layers
in the functional layer 40 may be adjusted according to the demands
of the design. It is worth noted that the functional layer 40, the
recess RC1, the recess RC2 and/or the lower recess RC3 may be
applied to other embodiments of the present disclosure according to
the demands of the design.
[0052] Referring to FIG. 6, FIG. 6 schematically illustrates a
partial cross-sectional view of a display device 104 according to a
fourth embodiment of the present disclosure. As shown in FIG. 6, in
some embodiments, the display layer 12 may include a dielectric
layer 51, a dielectric layer 52, a plurality of control elements
TFT, a dielectric layer 53, a planarization layer 54, a plurality
of display elements LE, a pixel defining layer 56 and a dielectric
layer 59. Each of the control elements TFT may include a
semiconductor layer SC, a source electrode SE, a drain electrode
DE, a gate electrode GE and/or a plurality of contact structures CT
connected to the source electrode SE or the drain electrode DE
respectively. The display layer 12 may further include a first
electrode 55, a second electrode 58 and a light emitting layer 57
disposed between the first electrode 55 and the second electrode
58, and each of the display elements LE may include a portion of
the first electrode 55, a portion of the second electrode 58 and a
portion of the light emitting layer 57 disposed between the first
electrode 55 and the second electrode 58. In some embodiments, the
area of one of the display elements LE (such as the frame of the
display element LE) may be defined by the bottom of the pixel
defining layer 56, but not limited thereto. The dielectric layer 51
may be disposed on the first substrate 14, and the dielectric layer
51 on the first substrate 14 may be served as a buffer layer and
provide buffer function, but not limited thereto. The dielectric
layer 51 may include single layer dielectric material such as
silicon oxide or silicon nitride, or the dielectric layer 51 may
include multi-layers structure including different dielectric
materials such as the multi-layers structure of silicon oxide and
silicon nitride, but not limited thereto. The semiconductor layer
SC may be disposed on the dielectric layer 51, and a portion of the
semiconductor layer SC may be doped to form the source electrode SE
and the drain electrode DE. That is, the source electrode SE and
the drain electrode DE may be a portion of the semiconductor layer
SC, but not limited thereto. In some embodiments, the semiconductor
layer SC may include a polycrystalline semiconductor layer, a metal
oxide semiconductor layer or other suitable semiconductor
materials. The dielectric layer 52 may be disposed between the
semiconductor layer SC and the gate electrode GE, and the
dielectric layer 53 may be disposed on the dielectric layer 52 and
the gate electrode GE. The contact structures CT may penetrate
through the dielectric layer 53 and the dielectric layer 52, and
may be directly electrically connected to the corresponding source
electrode SE or drain electrode DE. The planarization layer 54 may
be disposed on the dielectric layer 53 and the contact structures
CT. The first electrode 55, the light emitting layer 57, the second
electrode 58 and the pixel defining layer 56 may be disposed on the
planarization layer 54, the light emitting layer 57 may be located
in the opening formed by the pixel defining layer 56, and the
dielectric layer 59 may be disposed on the display element LE and
the pixel defining layer 56 to provide functions such as
encapsulation and/or planarization, but not limited thereto.
[0053] The materials of the gate electrode GE, the contact
structures CT, the first electrode 55 and the second electrode 58
mentioned above may include metal conductive materials (such as
aluminum, molybdenum, copper, titanium, tungsten or other suitable
conductive materials) or transparent conductive materials (such as
indium tin oxide (ITO) or other suitable transparent conductive
materials). The dielectric layer 52, the dielectric layer 53 and
the dielectric layer 59 may include single layer structure or
multi-layers structure including dielectric material (such as
silicon oxide, silicon nitride, aluminum oxide or other suitable
dielectric materials). In some embodiments, the gate electrode GE,
the first electrode 55 and the second electrode may respectively
include reflective electrode, transparent electrode or translucent
electrode. The above-mentioned reflective electrode may include the
electrode formed of silver, germanium, aluminum, copper,
molybdenum, titanium, tin, aluminum neodymium alloy (AlNd),
aluminum alloy (ACX), aluminum polymer (APC), etc. The
above-mentioned transparent electrode may include transparent
conducting oxide (TCO) electrode such as indium tin oxide electrode
or indium zinc oxide electrode. The above-mentioned translucent
electrode may include metal thin film electrode such as magnesium
silver alloy thin film electrode, gold thin film electrode,
platinum thin film electrode and/or aluminum thin film electrode,
but not limited thereto. The materials of the planarization layer
54 and the pixel defining layer 56 may respectively include organic
dielectric material (such as acrylic polymer material and/or
silicone polymer material) or other suitable materials that can be
photo-patterned, but not limited thereto. It is worth noted that
the structures of the driving circuit and the display elements in
the display layer 12 of the present disclosure are not limited to
what is shown in FIG. 6, and may include other suitable types of
driving circuits and/or display elements according to the demands
of the design.
[0054] In addition, in some embodiments, the functional layer 40
may include a plurality of sensing elements TS disposed between the
display layer 12 and the cover structure 20. In some embodiments,
the plurality of sensing elements TS may be disposed at intervals
and located between the plurality of display elements LE, but not
limited thereto. The sensing elements TS may include touch sensing
elements such as resistive type touch sensing element,
self-capacitive type touch sensing element, mutual-capacitive type
touch sensing element, optical type touch sensing element, force
sensing type touch sensing element or other suitable types of touch
sensing elements. In some embodiments, the sensing elements TS may
also include antenna, image sensor, pressure sensor, temperature
sensor and/or gas sensor, but not limited thereto. In other words,
the sensing elements TS may provide one kind of sensing function or
multiple kinds of sensing functions according to the demands of the
design. It is worth noted that the sensing elements TS and/or the
display layer 12 of the present embodiment may be applied to other
embodiments of the present disclosure according to the demands of
the design. In some embodiments, the shape of the recess RC3 may be
different from the shape of the recess RC1 according to the demands
of the design, for example, the recess RC3 may include a flat
bottom surface and/or non-arc-shaped sidewalls, but not limited
thereto. In some embodiments, the thickness H1 of the recess RC1,
the thickness H2 of the recess RC2 and the thickness H3 of the
recess RC3 may substantially be the same, but not limited
thereto.
[0055] Referring to FIG. 7A to FIG. 7D, FIG. 7A to FIG. 7D
schematically illustrate a cross-sectional view of a cover
structure in a display device according to some embodiments of the
present disclosure. In some embodiments, as shown in FIG. 7A, the
cover structure 20 may further include a plurality of spacer
structures 60 located in the peripheral region RG2 of the cover
structure 20, and the spacer structures 60 may be disposed between
the outer substrate 26 and the inner substrate 22. In addition, the
spacer structure 60 may include at least one first spacer 61 and at
least one second spacer 62 respectively disposed on the top surface
S2 of the inner substrate 22 and on the bottom surface S5 of the
outer substrate 26, such that the structural stability of the cover
structure 20 may be improved by the spacer structures 60, and the
risk of relative misalignment between the inner substrate 22 and
the outer substrate 26 when the folding is performed may be
reduced. The shape of the first spacer 61 and the second spacer 62
in the spacer structure 60 are narrow at the top and wide at the
bottom, but not limited to what is shown in FIG. 7A, and may be
adjusted according to the demands of the design. In some
embodiments, the first spacer 61 may include a concave 61R
corresponding to the second spacer 62, thereby achieving the effect
of improving the structural stability. In some embodiments, the
second spacer 62 may include a concave (not shown) corresponding to
the first spacer 61 to achieve the similar effect, but not limited
thereto. In addition, the sidewall SW1 of the recess RC1 may be
perpendicular to the top surface S2 of the inner substrate 22 in
some embodiments, but not limited thereto.
[0056] In some embodiments, as shown in FIG. 7B, the spacer
structure 60 may include a plurality of first spacers 61, and the
second spacers 62 may be partially located between two adjacent
first spacers 61 in the direction X, thereby achieving the effect
of improving structural stability. In some embodiments, the spacer
structure 60 may include a plurality of second spacers 62, and the
first spacers 61 may be partially located between two adjacent
second spacers 62 in the direction X, but not limited thereto. In
addition, the shape of the sidewall SW1 of the recess RC1 may be
adjusted according to the demands of the design, the included angle
between the sidewall SW1 of the recess RC1 and the bottom surface
S1 of the inner substrate 22 may be greater than 0 degree and less
than 90 degrees, or the sidewall of the recess RC1 may include
arc-shaped edge, but not limited thereto. In addition, the recess
RC1 may be located between the adjacent sub portions 22A, and the
adjacent sub portions 22A may be connected to each other, so the
recess RC1 may not expose the elements below the inner substrate
22.
[0057] In some embodiments, as shown in FIG. 7C, a thorough hole TH
may penetrate through the inner substrate 22 to divide the inner
substrate 22 into at least two sub portions 22A, but not limited
thereto. In some embodiments, the through hole TH may penetrate
through the inner substrate 22 along the direction Z and expose the
elements below the inner substrate 22. In some embodiments, the
through hole TH may be overlapped with the folding axis FX in the
direction Z, but not limited thereto. In some embodiments, the
through hole TH may extend along the direction Y (the direction
drawn in FIG. 1), but not limited thereto. The shape of the
sidewall SW2 of the through hole TH may be adjusted according to
the demands of the design, for example, the included angle between
the sidewall SW2 of the through hole TH and the bottom surface S1
of the inner substrate 22 may be equal to 90 degrees, but not
limited thereto. In the present embodiment, the through hole TH may
be formed by the treatment (such as etching, laser or cutting) on
the inner substrate 22. In some embodiments, the through hole TH
may be formed by the combination (for example, the sub portions 22A
are adhered at intervals) of the plurality of sub portions 22A of
the inner substrate 22, but not limited thereto.
[0058] In some embodiments, as shown in FIG. 7D, the inner
substrate 22 may include a plurality of through holes TH disposed
in the foldable region RG3, and there are four through holes TH
arranged at equal intervals in the present embodiment, but not
limited thereto. A distance DS may be included between the edge 24S
of the first adhesive 24 and the edge 22S of the inner substrate 22
and/or the edge 26S of the outer substrate 26 in the direction X
under a non-folded condition to reserve an extending space of the
first adhesive 24 when it is being folded. In some embodiments, the
distance DS may be greater than or equal to 1 micrometer and less
than or equal to 10 micrometers, but not limited thereto.
[0059] It is worth noted that the cover structure 20 of the present
disclosure is not limited to what is shown in FIG. 7A to FIG. 7D,
and the above-mentioned cover structure 20 shown in FIG. 7A to FIG.
7D may be applied to other embodiments of the present disclosure
according to the demands of the design.
[0060] Referring to FIG. 8, FIG. 8 schematically illustrates a
partial cross-sectional view of a display device 105 according to a
fifth embodiment of the present disclosure. As shown in FIG. 8, the
functional layer 40 may include a sensing layer 42, a retardation
layer 44 and a polarizer 46 disposed by stacking in the direction Z
in some embodiments. The sensing layer 42 may include the sensing
elements TS shown in FIG. 6 above and/or other suitable types of
touch sensing elements, and the retardation layer 44 may include
single layer or multi-layers of .lamda./2 retardation layer and/or
.lamda./4 retardation layer, but not limited thereto. In addition,
the relative position of each of the layers in the functional layer
40 may be adjusted according to the demands of the design, and is
not limited to what is shown in FIG. 8. In some embodiments, the
display layer 12 may include a driving circuit, a display element
layer 11 (such as the control element TFT and the display element
LE shown in FIG. 6 above) and an encapsulation layer 13 (such as
the dielectric layer 59 shown in FIG. 6 above) disposed on the
driving circuit and the display element layer 11, but not limited
thereto. It is worth noted that the functional layer 40 and/or the
display layer 12 of the present embodiment may be applied to other
embodiments of the present disclosure according to the demands of
the design.
[0061] Referring to FIG. 9, FIG. 9 schematically illustrates a
partial cross-sectional view of a display device 106 according to a
sixth embodiment of the present disclosure. As shown in FIG. 9, in
some embodiments, the functional layer 40 may be at least partially
disposed in the cover structure 20 or included in the cover
structure 20, for example, the sensing elements TS in the
functional layer 40 may be disposed in the cover structure, thereby
achieving the effect of integrating the structure and/or reducing
the total thickness, but not limited thereto. In some embodiments,
a plurality of sensing elements TS may be disposed on the top
surface S2 of the inner substrate 22, and the first adhesive 24 may
cover the sensing elements TS and be partially located between the
sensing elements TS and the outer substrate 26, but not limited
thereto. In some embodiments, at least a portion of the sensing
elements TS may be disposed on the bottom surface S5 of the outer
substrate 26 according to the demands of the design, and the first
adhesive 24 may cover the inner substrate 22 and be partially
located between the sensing elements TS and the inner substrate 22,
but not limited thereto. In the present disclosure, the shape and
the disposed position in the cover structure 20 of the sensing
elements TS are not limited to what is shown in FIG. 9, and may be
adjusted according to the demands of the design. In addition, when
the sensing elements TS includes opaque material (such as opaque
metal), the sensing elements TS may not be overlapped with the
display elements (such as the display elements LE shown in FIG. 6
above) of the display layer 12, and the effect of the sensing
elements TS on the display effect may be reduced, but not limited
thereto. It is worth noted that the sensing elements TS disposed in
the cover structure 20 of the present embodiment may be applied to
other embodiments of the present disclosure according to the
demands of the design.
[0062] Referring to FIG. 10, FIG. 10 schematically illustrates a
partial cross-sectional view of a display device 107 according to a
seventh embodiment of the present disclosure. As shown in FIG. 10,
in some embodiments, the above-mentioned functional layer may be
regarded as at least a portion of any one of the substrates in the
cover structure 20, for example, the inner substrate 22 may include
single layer or multi-layers of functional layer to achieve the
effect of integrating the structure and/or reducing total
thickness, but not limited thereto. For example, the inner
substrate 22 may include a retardation layer 21 and a polarizer 23
disposed by stacking, and the retardation layer 21 may include
.lamda./2 retardation layer and/or .lamda./4 retardation layer in
some embodiments, but not limited thereto. In the present
embodiment, the second adhesive 30 may be the thickest (for example
the thickness of the second adhesive 30 may be greater than 30
micrometers, but not limited thereto) glue layer in the stacked
layer above the display panel 10 and closest to the display panel
10, and the first adhesive 24 may be the thickest glue layer above
the second adhesive 30. The inner substrate 22 may be the layer
between the second adhesive 30 and the first adhesive 24 mentioned
above. In some embodiments, the adhesion between the retardation
layer 21 and the polarizer 23 may be performed through glue
material (such as the glue with thickness less than 25
micrometers), heat pressing adhesion, bonding adhesion, static
adhesion or other suitable adhesion methods. In addition, the inner
substrate 22 may include other functional films (such as
anti-reflection film) providing other effects in some embodiments.
It is worth noted that the inner substrate 22 including functional
films of the present embodiment may be applied to other embodiments
of the present disclosure according to the demands of the
design.
[0063] In summary, the cover structure formed of multiple layers of
materials is used to improve related characteristics of the display
device in the display device of the present disclosure. In
addition, in some embodiments, the folding effect, reliability,
lifespan and/or other related characteristics of the display device
may be improved by respectively controlling the thickness of the
inner substrate, the first adhesion layer and the outer
substrate.
[0064] Although the embodiments and advantages of the present
disclosure have been described above, it should be understood that
anyone with ordinary knowledge in the art can make change,
replacement, and modification without departing from the spirit and
scope of the present disclosure. In addition, the scope of
protection of the present disclosure is not limited to the
processes, machines, manufacturing, material composition, devices,
methods, and steps in the specific embodiments described in the
specification. Anyone who has ordinary knowledge in the technical
field can understand the processes, machines, manufacturing,
material composition, devices, methods, and steps developed
currently or in the future from the disclosed contents of the
present disclosure, and these can be used according to the present
invention as long as they can implement substantially the same
functions or obtain substantially the same results in the
embodiments described herein. Therefore, the protection scope of
the present disclosure includes the above-mentioned processes,
machines, manufacturing, material composition, devices, methods and
steps. In addition, each of the claims constitutes an individual
embodiment, and the scope of protection of the present disclosure
also includes combinations of each of the claims and embodiments.
The protection scope of the present disclosure shall be defined
according to the appended claims in the following.
[0065] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the disclosure. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
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